Aiming at the blocking problem of the interceptor network at the intake of the nuclear power plant, a detection method of interceptor network and related attachments based on high-resolution multi beam acoustic imaging is proposed. The high-frequency multi beam detection pool test of interceptor network and related attachments is carried out, in which the attachment is selected from the kelp, and the echo characteristics test of interceptor network and interceptor Network + kelp are analyzed. During the experiment, clear intercepting net and intercepting net + kelp acoustic image are obtained, which verifies the feasibility of using highresolution multi beam acoustic imaging method to detect intercepting net and related attachments. Through the comparison of the detection results of the interception network and the interception network + kelp, it is known that the echo highlights of the interception network will be enhanced after the kelp is attached. Therefore, the echo highlights can qualitatively describe the existence state of the attachments on the interception network.